New brakes, soft pedal, distribution blocks ?

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khuebner250

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So I have all new stopping components in my car, which is not road worthy yet, and have about 4-5" of travel in the pedal before it starts to firm up. Brakes are bled, no air, no leaks. Bled using a pressure bleeder, not vacuum.

Here's what I have:
68 barracuda manual drum brake car.
Frt Drdiff brembos
Rear Drdiff cobras
Braided flex lines
Drdiff 15/16 master
Drdiff adapter 4 to 2 hole
Stock manual rod
Distribution block from 69 valiant, not sure on brake configuration of said valiant.

Now I do have the distribution block that came off my car. There are a couple of frozen lines. That's why I used the valiant block.
Is there any difference between the two? 68 to 69 regardless of brake configuration? They look a bit different. Is there any way it can be causing my weird pedal?

IMG_20180903_103358566.jpg


IMG_20180903_103337204.jpg
 
Should be same. You either have air, or the shoes are not adjusted tight enough. If the drums are worn or turned oversize, the shoes may not fit "the curve" of the drums correctly. I would adjust them all up tight, and then check your pedal. Back the ajustment off equal "clicks" until the wheels spin with shoes still dragging. Drive around slow to wear them in a bit and re-check

Is this power or manual brakes? Manual brakes should be "rock hard" pedal. I would bet you still have air, somewhere. Sometimes, just leaving it set awhile and re-bleeding helps

Are the drums turned? Did you have the shoes "arced?" Good luck finding a shop who knows what that is LOL

post-62228-143142698387_thumb.jpg
 
Should be same. You either have air, or the shoes are not adjusted tight enough. If the drums are worn or turned oversize, the shoes may not fit "the curve" of the drums correctly. I would adjust them all up tight, and then check your pedal. Back the ajustment off equal "clicks" until the wheels spin with shoes still dragging. Drive around slow to wear them in a bit and re-check

Is this power or manual brakes? Manual brakes should be "rock hard" pedal. I would bet you still have air, somewhere. Sometimes, just leaving it set awhile and re-bleeding helps

Are the drums turned? Did you have the shoes "arced?" Good luck finding a shop who knows what that is LOL

View attachment 1715219367

No drums at all. It was a manual drum car but now has manual Drdiff discs all around.
 
Did you bench bleed the master cylinder?
 
Did you bench bleed the master cylinder?

No I've never needed to with a pressure bleeder. That's supposed to one of the benefits. Obviously I just need to go back to square one. I just got my wheels and am trying to get it on the ground as fast as possible. Apparently too fast. Lol. Never fails.

Keith
 
No I've never needed to with a pressure bleeder. That's supposed to one of the benefits. Obviously I just need to go back to square one. I just got my wheels and am trying to get it on the ground as fast as possible. Apparently too fast. Lol. Never fails.

Keith

Just an idea, something isn’t quite right.

Obviously you’re getting fluid to all the calipers if you’ve bled everything, and your distribution block is just that, a distribution block, so there’s no proportioning going on there or anything to fail inside the block.

I have gotten a brand new in the box master cylinder that was no good, although that wasn’t from Cass and I don’t think that would be my first guess. Still, as you go through from square one it’s worth considering that just because parts are new doesn’t necessarily mean theyre working properly.
 
Should be same. You either have air, or the shoes are not adjusted tight enough. If the drums are worn or turned oversize, the shoes may not fit "the curve" of the drums correctly. I would adjust them all up tight, and then check your pedal. Back the ajustment off equal "clicks" until the wheels spin with shoes still dragging. Drive around slow to wear them in a bit and re-check

Is this power or manual brakes? Manual brakes should be "rock hard" pedal. I would bet you still have air, somewhere. Sometimes, just leaving it set awhile and re-bleeding helps

Are the drums turned? Did you have the shoes "arced?" Good luck finding a shop who knows what that is LOL

View attachment 1715219367

I used to use one back in the 70's that exact unit but yours is much nicer looking,
 
So I have all new stopping components in my car, which is not road worthy yet, and have about 4-5" of travel in the pedal before it starts to firm up. Brakes are bled, no air, no leaks. Bled using a pressure bleeder, not vacuum.

Here's what I have:
68 barracuda manual drum brake car.
Frt Drdiff brembos
Rear Drdiff cobras
Braided flex lines
Drdiff 15/16 master
Drdiff adapter 4 to 2 hole
Stock manual rod
Distribution block from 69 valiant, not sure on brake configuration of said valiant.

Now I do have the distribution block that came off my car. There are a couple of frozen lines. That's why I used the valiant block.
Is there any difference between the two? 68 to 69 regardless of brake configuration? They look a bit different. Is there any way it can be causing my weird pedal?

View attachment 1715219351

View attachment 1715219352

Those are switches so if you loose pressure in the front or rear it turns the brake light on, the proportioning valve is another part and I don't think a 4 wheel drum system had them. you should use a adjustable proportioning valve so the rears don't lock up on hard stops.
 
I went thru a similar sounding scenario on my demon. Was the plunger arm in the booster on mine. Couple turns out and it fixed a lot of nightmares. Thought i measured for that correctly but apparently i suck
 
Those are switches so if you loose pressure in the front or rear it turns the brake light on, the proportioning valve is another part and I don't think a 4 wheel drum system had them. you should use a adjustable proportioning valve so the rears don't lock up on hard stops.

From what I know the stock distribution block for 4 wheel drums will work on 4 wheel discs. That's per Cass, no proportioning valve needed. I do have good fluid at all 4 corners just the pedal sucks. Just didn't know if the 2 blocks I have are anyway different, since they are different shapes. Here is the 68 one.

153600155081974630750670007846.jpg
 
Should be a hard pedal,and you said pressure bleeder so trapped air is unlikely. I would start with master cylinder, and bench bleed it just because. If it has trapped air, pressure bleeding may not purge it. And you will know if its spongy in the vise.
Pedal rod allowing master to return fully?
Drum brake residual valves are 10 psi,where calipers hold back 3 psi. Dont think it will affect the pedal feel though.if wire isnt connected to prop valve, use an ohmmeter to make sure circuit isnt closed.
 
The 15/16 master cylinder gives a long pedal travel.
Does pumping the pedal change the travel?
If not, it's just the nature of the 15/16 master.
 
Not sure if this video will play
Should be a hard pedal,and you said pressure bleeder so trapped air is unlikely. I would start with master cylinder, and bench bleed it just because. If it has trapped air, pressure bleeding may not purge it. And you will know if its spongy in the vise.
Pedal rod allowing master to return fully?
Drum brake residual valves are 10 psi,where calipers hold back 3 psi. Dont think it will affect the pedal feel though.if wire isnt connected to prop valve, use an ohmmeter to make sure circuit isnt closed.

Already checked continuity, circuit is open. Have good rod return, no binding. If anything I gained about 3/16" of throw, due to the 4/2 hole adapter. I also cracked the lines at the master but just with pressure from the bleeder. I wasn't able to stroke the master and crack the lines at the same time.
 
From what I know the stock distribution block for 4 wheel drums will work on 4 wheel discs. That's per Cass, no proportioning valve needed. I do have good fluid at all 4 corners just the pedal sucks. Just didn't know if the 2 blocks I have are anyway different, since they are different shapes. Here is the 68 one.

View attachment 1715219398

I can't believe no proportioning valve, what calipers, 4 pistons front and single piston rear ? It takes more fluid to fill the 4 pistons than a single piston, is the switch centered, once it is pushed to one side it stays there till there is enough pressure to push it back to center. Check it with a ohm meter and see if the switch is grounded. From the video it looks like air is in the system or the caliper pistons are pulling back when you let up on the pedal. How much gap between the pads and rotors.
 
The 15/16 master cylinder gives a long pedal travel.
Does pumping the pedal change the travel?
If not, it's just the nature of the 15/16 master.

Yeah, not at all.

Yes, the 15/16” master gives a longer travel than a 1-1/32” master, but it’s still not a “long pedal travel”. The pedal should still be hard and still stop well before it gets anywhere near 5-6” of travel.

How about now.



Holy cow. There’s no pedal at all. There’s air trapped in the system somewhere, or something is installed improperly.
 
From the video, theres nothin there. Im putting my money on air in master,or master is bad.
Find a way to block or strap pedal down and crack a line at the master. I have a rod and a stopper for bleeding brakes manually by myself. Takes longer buy i dont need to ask for help either.
One guy has good success reverse bleeding, but you have to use a susction gun to remove fluid from master.
 
No drums at all. It was a manual drum car but now has manual Drdiff discs all around.
You said

"68 barracuda manual drum brake car." and that is what I thought you had. You SURE you CERTAIN the bleeders are on the top most of the calipers?
 
Can you post a picture of the front caliper and the rear caliper and where the bleeders are ?
 
Can you post a picture of the front caliper and the rear caliper and where the bleeders are ?

Rear wheels are currently on. So no pic showing bleeder but they were up when I bled em and put the wheels on. Did all 6 also

IMG_20180421_172200765.jpg


IMG_20180401_095418526.jpg
 
If you pump the pedal does it ever get better?
 
I went thru a similar sounding scenario on my demon. Was the plunger arm in the booster on mine. Couple turns out and it fixed a lot of nightmares. Thought i measured for that correctly but apparently i suck
Same here. Went from a single pot power to a double pot power. Thought I calculated it out, but still had a soft pedal. Readjustment of the rod fixed that.
 
I fought with a model A street rod for a long time and finally made a vacuum tank that I sucked down with a a/c vacuum pump made a glass jar to collect the fluid and watch for air and 2 qts of brake fluid later I had a rock hard pedal. Air was trapped somewhere.
 
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